In recent years, it has become customary to make a diagnosis of fuel mileage or driving behavior of a vehicle based on driving data that are recorded in an electronic control unit (hereinafter referred to as “ECU”) installed in the vehicle. For example, in view of the tendency of the user to prefer driving the vehicle with low fuel consumption, driving data (vehicle speed data, etc.) stored in the ECU in the vehicle over a plurality of driving cycles are read, the diagnosis of fuel efficiency or driving behavior of the vehicle is made based on the read driving data, and the results of the diagnosis are presented to the user {see Abstract, a vehicle speed sensor 11A shown in FIG. 1, FIG. 10, and Table 1 of U.S. Patent Application Publication No. 2012/0065874 (hereinafter referred to as “US2012/0065874A1”)}.
There has also been proposed a technology for calculating a traveling speed and a traveled distance using an acceleration sensor {see Abstract of Japanese Laid-Open Patent Publication No. 10-170303 (hereinafter referred to as “JP10-170303A”)}.